Learning about the brain, body and how it all connects

Main menu

Tag Archives: Hormones

Scientists have pursued every possible avenue to try to figure out why we keep getting fatter. They’ve explored our genes, our brains, our hormones and our gut bacteria, not to mention our fatty, sugary diets and sedentary lifestyles. Now, a recent study has come out blaming our expanding waistlines and poor health on our parents’ behaviors before we were born.

My newest article is up on The Atlantic, discussing recent research on the impact a mother’s diet has on her offspring’s health, affecting our brains and subsequently our bodies. This line of research isn’t new — otherstudies have shown links between a woman’s health during pregnancy and her child’s weight later in life — but this is one of the first to provide a potential explanation for this phenomenon by looking in the brain at some crucial hunger hormones.

However, you can’t blame all of your problems on your parents; what you eat still has a major impact on how these brain changes manifest:

Now, I’m all for shifting blame away from myself and onto my parents, but I feel that, like every possible explanation behind the obesity epidemic, this is only one piece of the puzzle. Genes undoubtedly play a role in body mass, fat percentage, and metabolism, but so does what you eat and how many calories you burn through physical activity…The problem of obesity, like so many health and social issues we face today, is that there isn’t just a single contributor to the problem. If there were, it would have been solved by now.

It’s hard being a young woman these days. Chivalry is dying, but many glass ceilings are still firmly in place. We’re supposed to have it all but sacrifice nothing, balancing choosing a career path and a life partner. We can delay having kids by putting our eggs in the freezer next to our vodka, but our similarly aging male partners’ sperm might handicap our chances of having healthy offspring, with higher risks for autism and schizophrenia linked to paternal age.

And now it turns out that hormonal contraception, or The Pill, our revolutionary defense against the inherent misogyny of biology, could be tricking us into choosing the wrong men.

Two studies led by Dr. Craig Roberts from the University of Stirling in Scotland have suggested that taking oral contraception can change your attraction to and preferences for men. In an initial study, Dr. Roberts and his team asked women who were about to go on the pill to rate the attractiveness of a selection of male faces, considering them as both short-term and long-term partners. They were then tested again approximately three months later to see if their preferences had changed. Sure enough, in the second test session women who had started hormonal contraception had significant shifts in their partner preferences, now preferring significantly less masculine-looking faces than they had three months earlier. Conversely, control women who had not started the pill did not differ in their choices from the first session.

In a follow-up study, real couples who had met while the woman was either on or off the pill were assessed for the male partner’s masculinity. This involved complex photo manipulation and judgment of the pictures by outside individuals, who ranked the male faces on features of masculinity. Though these methods are a bit fuzzy and convoluted, the researchers’ results (surprise surprise) matched those of the first study. That is, male partners of women who were already on the pill when they met were judged to be significantly less masculine looking than men whose female partners were not taking hormonal contraception.

Notable masculine features include squarer face-shapes, stronger jawlines and less prominent cheekbones, all of which are typical signifiers of higher levels of testosterone. The authors claim that this shift to preferring less masculine features is perhaps a transition towards subconsciously choosing more faithful or nurturing partners after starting contraception, which can be beneficial for long-term relationship success. However, a major problem with these partner preference shifts is that presumably at some point during a mature, adult, monogamous relationship women go off their contraception, potentially reversing back their partner preferences. This can lead to dissatisfaction in the relationship, female philandering, and some very awkward conversations: “Sorry honey, you used to do it for me, but now I find you much too feminine for my liking.”

Another major concern is that genetically we are supposed to be drawn towards mates who are more dissimilar to ourselves. This is evolutionarily advantageous, as greater parental genetic variability reduces the likelihood of heritable diseases in the offspring. Basically, your children are less likely to be born with a genetic disorder if your and your partner’s DNA are more different. It has been proposed that some of the shifts in partner preferences after initiating oral contraception are actually towards men who are more genetically similar to you, which can be problematic, but there are no theories yet as to why this might be the case.

However, it’s a pretty big stretch to say that preferring men with slightly rounder faces means you’ve undergone a major change in your list of demands for your partner’s personality and genetic makeup (if you happen to have such a list for that). Also, the first study was performed with only 18 women in the experimental condition, which is a pretty tiny population for measuring significant differences in behavior. So the researchers conducted another follow-up experiment to investigate if these effects mapped onto real-world behavior. Researchers tested 2500 women (a much better sample size) in stable relationships who had started dating their partner while they were either on or off the pill and compared them on several measures of relationship and sexual satisfaction.

Women who first met their partners while taking oral contraception scored significantly lower on measures of sexual satisfaction and rated themselves less physically attracted to their partners than women who met their partners while not on the pill. However, the women taking the pill did have higher overall non-sexual relationship fulfillment and financial stability than those who were off the pill. In a related twist, women who were on contraception were actually less likely to have separated from their partners than women not on the pill when they chose their partners.

So what’s the takeaway from this? Don’t take oral contraception and you’ll have better sex with a more attractive man, but will be more likely to break up with him in the future? Go on the pill and you’ll be dissatisfied sexually by your unattractive mate and your offspring will have genetic disorders, but at least you’ll stay together forever? Maybe. Or maybe being on the pill leads you to choose partners based more on long-term than short-term payouts. Or it means that you have different priorities in your partner preferences to begin with. Either way, make the decision wisely, your future children may depend on it.